The present invention relates to an indwelling needle which is used in infusion of a liquid medicine, blood and the like or in blood collection and the like by being stuck in a peripheral vein, under a skin, etc.
For infusion from a peripheral vein in the back of a hand, it is required to curve an infusion route. Therefore, an indwelling needle of a winged needle (with wings) type (PSV) is used. The indwelling needle of a winged needle type has a hollow needle and a fixing wing which is externally fitted and fixed on a distal end of the hollow needle and fixed on a skin.
In the foregoing indwelling needle, a hollow needle made of metal is mainly used. When such a hollow needle made of a metal is used, a blood vessel might be damaged with an edge of the hollow needle during indwelling of the needle in the blood vessel. Accordingly, there was a problem that the indwelling needle could not be used for administration of a liquid medicine over a long period of time or indwelling in a blood vessel over a long period of time.
In the case that an indwelling needle is used for administration of a liquid medicine over a long period of time or indwelling in a blood vessel over a long period of time, an indwelling needle was used which comprises a cover needle made of plastics, a fixing wing externally fitted and fixed on a distal end of the cover needle and an inner needle made of metal which is detachably inserted into the cover needle and whose distal end is projected forwards from the cover needle. In infusion, the inner needle and the cover needle are first stuck into a blood vessel of a patient, the inner needle is then drawn out from the cover needle and only the cover needle is indwelled in the blood vessel to perform infusion. However, since the cover needle made of plastic tends to kink, it is difficult for the cover needle to be curved for fixing on a patient""s arm with tape or the like.
An indwelling needle solving such a problem has been proposed in U.S. Pat. Nos. 4,177,809 and 5,163,913 and has been commercialized by Nippon Becton Dickinson Company, Ltd. as Intima (trade mark). However, since the foregoing needle is complicated in structure and costly, it has not been widespread in Japan.
The present invention aims to provide an indwelling needle which, although a cover needle is made of plastics, does not kink so that a procedure of curving the cover needle to fix it on an arm or the like of a patient with a tape or the like for infusion is easily practiced. With the indwelling needle, infusion or blood collection from a peripheral vein in the back of a hand or the like is easily and satisfactorily conducted. Additionally, the indwelling needle is simple in structure and can be manufactured at low cost.
For attaining the foregoing aim, the present invention is characterized by an indwelling needle comprising (A) a flexible cover needle made of plastic, (B) a fixing wing externally fitted and fixed on a distal end of the cover needle, (C) a cover needle hub mounted on a proximal end of the cover needle, and (D) an inner needle which is removably inserted through the cover needle and the cover needle hub and the distal end of which projects forwards from the cover needle, with a kink preventing means for preventing kink of a portion of the cover needle between the fixing wing and the cover needle hub being provided on the cover needle.
The kink preventing means may be a protecting tube externally fitted on the cover needle or protecting members mounted around the cover needle and being spaced apart from each other.
In certain embodiments, the fixing wing may have a fixing means for releasably fixing the cover needle and the inner needle.
In certain embodiments, the fixing wing may comprise a holding tube externally fitted and fixed on the cover needle, a pair of wing parts projecting outwardly from the holding tube to the right and left sides, and a pair of connecting portions for connecting an upper surface or a lower surface of each wing part and the holding tube, and the fixing means may be a means for fixing the cover needle and the inner needle by bringing both of the wing parts relatively close to each other to press the holding tube and the cover needle via the respective connecting portions diametrically inward.
In certain embodiments, an inner needle hub is mounted on a proximal end of the inner needle, and an inner needle housing which is interposed between a proximal end of the cover needle hub and the inner needle hub, comprises (A) an inner tube in which the inner needle is inserted, (B) an outer tube which is externally fitted on the inner tube, and (C) a sleeve which is externally fitted on the inner tube, a distal end of which is fixed on the inner needle housing, a proximal end of which is externally fitted and fixed on a distal end of the inner needle hub, and which is housed between the inner tube and the outer tube in an axially folded state and is axially extended when the inner needle is removed from the cover needle and the cover needle hub to cover a portion of the inner needle which is situated on a more proximal side than the inner tube.
In some cases, the inner needle housing may include a pressing portion capable of pressing against an outer surface of the inner needle in a state that the inner needle 5 is slidable against the pressing portion, and capable of deforming diametrically inwards by its own resilient force to have an inner diameter which is smaller than an outer diameter of the inner needle after the inner needle is drawn out backwards from the pressing portion.